Performance lighting systems have long employed large numbers of fixtures each selected and preadjusted to produce a beam of a particular size, shape, and color aimed at a fixed location on the stage. The only beam parameter variable during the performance is intensity, and the character of the lighting effect onstage is adjusted solely by changing the relative intensities of the variety of fixtures provided.
"Memory boards" allowing a user to store and subsequently recall "presets", each of which represents a digitally-coded record of the desired intensity for each of a plurality of discretely-controllable fixtures or group of fixtures in a lighting effect have been known for decades, and the design of the modern, software-based, CRT-oriented memory board as disclosed in U.S. Pat. No. 3,898,643 has evolved to the point that such units are capable of--and lighting designers have come to demand--very complex effects. Further, lighting designers can choose from among various types and models of memory board differing in the manner in which they store cues (for example "tracking" versus "preset" boards) and in their operating protocols--and may have strong preferences for particular types and models as more familiar and/or more appropriate for a given production.
Despite the complexity of these dimming effects, lighting systems employing only fixtures controlling only intensity have the disadvantage of the need for many more fixtures than are used at any one time--or would be required were the fixtures capable of varying other beam parameters during the performance. There is the direct cost to buy or rent the large number of fixtures required plus their associated supporting structure, dimming equipment, and interconnecting cables as well as the time and labor required to install, adjust, and service this amount of equipment.
The electronic storage and recall of stored intensity values using "memory boards" has thus had no positive effect on the size of lighting systems, and indeed by removing the practical limits on the number of control channels and presets which had been imposed by manual presetting consoles, the adoption of such electronic memory boards has lead to a substantial increase in the size of the lighting systems which employ them.
It has long been apparent that were fixtures able to change beam parameters in addition to intensity (like color, beam size, or even azimuth and elevation), either as the result of integral remotely actuatable mechanisms and/or devices (like color changers) which may be retrofitted to conventional fixtures, then lighting effects could be varied by actually changing the fixtures' beams rather than dimming between otherwise identical fixtures with different fixed adjustments. Each such "multi-variable" fixture could, over the course of the performance, duplicate the results it currently requires many fixtures to achieve--as well as adding dynamic changes in the beam to the lighting effects possible--requiring fewer fixtures to produce a given lighting design with consequent savings.
The viability of employing fixtures with remotely adjustable beam size, color, shape and/or angle as a method of reducing system size depends upon a suitable control system, first disclosed in U.S. Pat. No. 3,845,351, capable of storing desired parameter values for each of the controlled parameters in each of the desired lighting effects and of automatically conforming the fixture's beam varying mechanisms to those values.
Similar systems were subsequently disclosed in U.K. Pat. No. 1,434,052 and U.S. Pat. No. 4,392,187, and today, the rental of such systems to concert, television, and theatrical productions is a multi-million dollar industry.
There have, however, been unexpected difficulties with developing a truly efficient embodiment of such a control system.
The most common approach employs completely custom hardware and software.
Any such custom control system is very expensive because the number of such systems built relative to even the limited number of conventional lighting memory boards produced is very small. No significant volume cost reductions are possible and the considerable investment in the "ground up" development of a specialized control system handling up to eight times the amount of data per fixture (relative to a conventional console) can be amortized across only a limited number of units.
Further, it is inevitable that the features and controls provided by any specialized controller will not meet the requirements of all users, and that changes will be requested by users over time. This requires a further investment by the manufacturer in hardware and software revisions, amortizable across the same relatively limited volume.
These problems have proved particularly relevant because, despite the long-held assumption that remotely adjustable devices (whether color changers, remote yokes, or multi-variable fixtures) would be used on an exclusive basis to maximize the purported gains in system efficiency, due to a variety of factors including the high cost of such equipment, it has instead been the case that the number of such devices per system may vary widely and that, contrary to expectations, devices of several different types (such as both color changers and remote fixtures) may be employed in the same system, together with conventional fixtures.
These "real world" conditions further complicate the development of an efficient control system for "multi-variable" fixtures, because previously-disclosed control systems for such fixtures had not been designed to provide for the control of large numbers of conventional fixtures in intensity only. Such prior art control systems lacked many of the features found in modern "memory boards", and failed to provide means to reconfigure their outputs, display modes, and internal operation to reallocate channel capacity allotted to multi-variable fixtures to the control of a larger number of conventional fixtures. Each conventional fixture used with a system controlling five parameters of a multi-variable fixture displaces one such multi-variable fixture, wasting the other four channels allotted to the control of the adjustable parameters other than intensity.
As a consequence of the inability of previously-disclosed custom control systems for multi-variable fixtures to address the unrecognized problem of the need to provide for the control of both large numbers of conventional fixtures as well as at least one type of multi-variable fixture in the same lighting system, entertainment lighting productions employing both have frequently found it necessary to use both a conventional memory board for the conventional fixtures and at least one specialized control system for multi-variable fixtures and devices--and two or more operators with no coordination between them save written notes and verbal cues. The process of writing and revising cues spread across two or more consoles with different operators and protocols is clearly more complex and potentially error-prone. During the performance, undesirable discrepancies and/or timing errors may arise in the execution of cues, and therefore in the responses of the fixtures controlled by the two systems to events onstage.
Even were builders of such custom control systems to add the hardware and software required for the system to provide the additional channel capacity required for large numbers of conventional fixtures as well as the features expected of modern "memory boards", it would produce a substantial increase in both the development task and the cost of the system, for the reasons described above.
Further, without an exceptional effort, the resulting system could not duplicate the features and operating protocols of all of the types and models of memory boards in common use--and therefore would not full satisfy the preferences of all designers.
Alternatively, some recent builders of "multi-variable" fixtures, typified by the Pana-Spot.TM. multi-variable fixture (of Morpheus Lights, San Jose, Calif.), have not employed a custom control system, but instead have configured their fixtures to allow the use of any conventional lighting memory board, such as disclosed in U.S. Pat. No. 3,898,643.
While this approach spares the fixture manufacturer the development of a custom control system, the use of conventional memory boards to control "multi-variable" fixtures has had important disadvantages.
While such a console records and displays the variables for each fixture, all variables for all fixtures are presented uniformly as two numbers: the channel number and a percentage value. A time consuming reference to a list or table is required to determine that the beam size for fixture #8 is controlled by channel #93. Conversely, the CRT display of values is useless without conversion.
Further, such consoles generally provide input devices allowing manual or keyboard adjustment of only a single output or group of outputs at a time. Therefore, most recording operations for remote fixtures require a lengthy series of adjustments, with reference to a table of 100 or more functions between each one.
Such consoles also do not provide data manipulation features unique to multi-variable fixture use, nor can their outputs be reconfigured to provide resolutions greater than or less than 8-bits.
One might suggest modifying the standard memory controller with more appropriate input devices, display modes, outputs, and software, but that contradicts many of the advantages of using an existing controller.
Even were such modifications performed, the memory board may become more specific to the requirements of the controlled multi-variable fixture or device for which it is adapted and potentially less suitable for other types of fixture or device with different requirements. The hardware and computational workload demanded by more sophisticated features unique to the requirements of multi-variable fixtures may also exceed the capabilities of the memory board's original hardware design.
In principle, a conventional memory board used to store parameter values for multi-variable fixtures can also be used to store desited intensities for conventional fixtures.
In fact, the number of discretely-controllable channels demanded by multi-variable fixtures relative to the number of channels offered by typical memory boards used in the application has been so large, that in lighting systems employing significant numbers of multi-variable fixtures, such memory boards have insufficient channel capacity to permit discretely controlling all parameters of each fixture, much less provide the additional channels required to control large numbers of conventional fixtures. Furthermore, the user would then be unable to employ other types and models of memory boards which were unmodified, despite the fact that for the production, they might be more appropriate or desirable for the control of the conventional fixtures.
Because both the number and relative proportion of multi-variable and conventional fixtures and devices will vary widely from production to production, such a prior art memory board adapted for use with multi-variable fixtures would also have to be field-reconfigurable to compensate for the particular number and relative proportion of connected fixtures, and capable of supporting the memory and computational workload of all possible combinations.
It is the object of the present invention to provide a uniquely elegant solution to the above-described difficulties with prior art approaches to the control of systems employing both conventional fixtures and multi-variable fixtures and devices.